United States Patent [i9] [H] Patent Number: 5,046,238
Daigle et al.  Date of Patent: Sep. 10, 1991
 METHOD OF MANUFACTURING A MULTILAYER CIRCUIT BOARD
 Inventors: Robert Daigle, Sterling; Samuel
Malbaurn, Dayville, both of Conn.;
David Noddin, Eau Claire, Wis.;
G. Robert Traut, Danielson, Ct.
 Assignee: Rogers Corporation, Rogers, Conn.
 Appl. No.: 493,975
 Filed: Mar. 15, 1990
 Int. Cl.s H05K3/36
 U.S. CI 29/830; 29/739;
29/848; 361/412; 428/422
 Field of Search 204/15; 29/830, 739,
29/846; 361/412, 414
 References Cited
U.S. PATENT DOCUMENTS
3.835,531 9/1974 Luttmer 29/830 X
4,634.631 1/1987 Gazit et al 428/422 X
4,788,766 12/1988 Burger et al .' 29/848 X
4,818.728 4/1989 Rai et al 29/739 X
4,868,350 9/1989 Hoffarth et al 29/830 X
Methods of fabricating multilayer circuits are presented. In accordance with the present invention, a plurality of circuit layers comprised of a dielectric substrate having a circuit formed thereon are stacked, one on top of the other. The dielectric substrate is composed of a polymeric material capable of undergoing fusion bonding such as a fluoropolymeric based substrate. Fusible conductive bonding material (e.g. solder) is applied on selected exposed circuit traces (prior to the stacking step) whereupon the entire stack-up is subjected to lamination under heat and pressure to simultaneously fuse all of the substrate and conductive layers together to form an integral multilayer circuit having solid conductive interconnects.
12 Claims, 4 Drawing Sheets